I like diving in Canadian lakes - there, I can practice my skills without the unwanted distraction of stunning scenery.
I can't compare zeagle vs halcyon vs oxycheq. However,
based upon what I have read here on SB, many who can afford halcyon buy it, and (almost) everyone that buys halcyon loves it. If discussing wings only, more posts sing the virtues of the oxycheq Mach V than any other wing. Finally, those who begin with zeagle tend to stay with zeagle. I don't think that there is a bad choice in your field of candidates.
I believe that a SS BP is about 6# while an AL is about 2#, so the difference is not great. However, the difference will become most apparent: (1) in warm water; and (2) when Air Canada charges you for extra baggage weight. For reasons 1 and 2 I opted for AL.
A note on cold water diving - I did my one year of diving in a wetsuit in Waterton Lake. I finally got a drysuit and LOVE it - it is the single most expensive piece of gear I bought (I opted for a DUI TLS 350 Signature Series), and the piece of kit which makes me most happy. If you do get a drysuit and if you ever plan to dive in BC (beautiful) I would strongly recommend reinforced kneepads as shore entries over shell-encrusted rocks can be killer on the suit. Also, bellows pockets on the legs are awesome for putting gear into.